Gents,
Thanks all for the mostly reassuring comments and advice. After reading your thoughts I had another bad thought of my own. In the winter work, I replaced all the valves and two of the guides and I could not recall if I had lubricated the valve shafts before assembly. This would not be a good thing regardless, but I think the metallic dust showed up too soon to be something washed down from the guides. Nevertheless, feeling a deep fear, I pulled off the rocker covers to see if I could detect any problem. Of the two guides who's tops I could glimpse through the springs, there appeared to be no problem and things looked moist. Anyway, I gave a heavy squirting of oil through the springs and towards the guides, just for peace of mind. So far, still no noticeable bad sounds.
Erling, good point about the oil filter and, of a sense, good to hear that someone else has seen this without catastrophic results.
Trevor (54A10), I like the idea of the empirical approach of measuring the dross to assure that it is diminishing. I like, even better, the idea of it being moth wings, but I assume that was a bit of kidding about. As for 3-litre soda bottles, maybe the rate at which I change oil will parallel the rate at which my kids can consume Diet Coke.
Trev, I did not replace the timing side bearing (except about 1400 miles ago). Again, good to hear from another experienced member that this was not a disastrous phenomenon. Hey, but time will tell. If I could just go a few years without major rebuilding I would still be happy, I think. (I may have a psychological problem that requires me to be working on the bike in order to be happy.)
Richard L.
